Intra-gastric fastening devices are disclosed herein. Expandable devices that are inserted into the stomach of the patient are maintained within by anchoring or otherwise fixing the expandable devices to the stomach walls. Such expandable devices, like inflatable balloons, have tethering regions for attachment to the one or more fasteners which can be configured to extend at least partially through one or several folds of the patient's stomach wall. The fasteners are thus affixed to the stomach walls by deploying the fasteners and manipulating the tissue walls entirely from the inside organ. Such fasteners can be formed in a variety of configurations, e.g., helical, elongate, ring, clamp, and they can be configured to be non-piercing. Alternatively, sutures can be used to wrap around or through a tissue fold for tethering the expandable devices. Non-piercing biased clamps can also be used to tether the device within the stomach.